Question
What is retention explain with example.
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Answer
→ Retention of configuration is the preservation of the spatial arrangement of bonds to an asymmetric centre during a chemical reaction or transformation.
→ In general, if during a reaction, no bond to the stereocentre is broken, the product will have the same general configuration of groups around the stereocentre as that of reactant.
→ Such a reaction is said to proceed with retention of the configuration.
→ Consider as an example, the reaction that takes place when (-)-2-methylbutan-1-ol is heated with concentrated hydrochloric acid.
→ It is important to note that configuration at a symmetric centre in the reactant and product is same but the sign of optical rotation has changed in the product.
→ This is so because two different compounds with same configuration at asymmetric centre may have different optical rotation. One may be dextrorotatory (plus sign of optical rotation) while other may be laevorotatory (negative sign of optical rotation).
→ In general, if during a reaction, no bond to the stereocentre is broken, the product will have the same general configuration of groups around the stereocentre as that of reactant.
→ Such a reaction is said to proceed with retention of the configuration.
→ Consider as an example, the reaction that takes place when (-)-2-methylbutan-1-ol is heated with concentrated hydrochloric acid.
→ It is important to note that configuration at a symmetric centre in the reactant and product is same but the sign of optical rotation has changed in the product.
→ This is so because two different compounds with same configuration at asymmetric centre may have different optical rotation. One may be dextrorotatory (plus sign of optical rotation) while other may be laevorotatory (negative sign of optical rotation).
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